Joint for oil-filled cables



y 93 1.. KUNST 1,956,723

JOINT FOR OIL FILLED CABLES Filed June 25, 1931 Patented May I, 19341,956,723 JOINT FOR OIL-FILLED CABLES Ludwig Kunst,Berlin-Charlottenburg,

Siemens-Schuckertwerke Aktienassignor to Germany,

gesellschaft, Berlin-Siemensstadt, Germany, a corporation of GermanyApplication June 25, 1931, Serial No. 546,745

In Germany July 4, 1930 2 Claims.

My invention relates to joints for oil-filled multi-conductor cables andhas for its primary object to provide an improved protective seal forthe oil-filled channels as well as an oil-conveying connection ofimproved construction between contiguous cable lengths.

It is old and well known in the art to provide individualinsulated-conductors of an oil-filled multiple-conductor cable with aseamless metal sheath and to cover the stranded lead-sheathed insulatedconductors with an additional seamless metal sheath, the interspacesbetween the common seamless metal sheath and the stranded metalsheathed,insulated conductors being filled with oil. With a cable of that kind,there is danger that the outer lead sheath may become damaged and thuspermit the oil between this sheath and the stranded single-conductorcables to absorb moisture. In this event, should the adulterated 39 oilpenetrate into the joint box and reach the point where the conductorsare joined and particularly their insulation, the electric properties ofthe joint will be so impaired that a breakdown is liable to occur.

In order to overcome this drawback, my invention contemplates a socketconnection of improved construction between the end of the common leadsheath and the individual insulated conductors at points where the cableenters and leaves the joint box. For the purpose of providing anoil-tight closure of the oil-filled spaces, the socket connection may beapplied at one end to the common lead sheath which surrounds theinsulated conductors and at its other end provided with tubularextensions attached to the leadsheathed insulated conductors of thecable, oiltight seals being formed between said socket connection andthe common lead sheath and between said socket connection and the leadsheaths ofthe individual insulated conductors.

An illustrative embodiment of my invention is shown on the drawing inwhich Figure 1 is a longitudinal section of a joint connection foroil-filled multi-conductor cables constructed according to the presentinvention.

Figure 2 is a cross-section of Figure 1 on the line A-B.

Figure 3 is a longitudinal section of a cable joint connection similarto that shown in Figure 1 in which the oil-filled chambers of successivesections .of the multi-conductor cable are connected by a tubularconnection arranged interiorly of the joint box or housing.

Figure 4 is a longitudinal section of a similar joint connection inwhich the oil-filled chambers of successive sections of the cable have atubular oil connection arranged exteriorly of the joint box or housing.

In the drawing, the numerals 1 and 2 indicate two insulated conductorsof a cable which ex- 80 tends into a joint box 3. Said insulatedconductors are provided with metal sheaths 11 and 12, respectively, andsurrounded by a common lead sheath 4. 5 and 6 are the insulationwrappings at the joints between contiguous lengths of the conductors 1and 2. In order to provide an eifective oil seal for the spaces betweenthe common lead sheath and the individual lead sheaths of the insulatedconductors and between said individual lead sheaths, and thus preventingthe oil from penetrating into the joint box 3 where it would reach theinsulating wrappings 5 and 6, a socket connection 7 may be provided andattached with an oil-tight seal to the common lead sheath 4. Tubularextensions 13 may be similarly attached to the individual lead sheaths11 and 12 for the insulated conductors. The oil-tight joints between thecommon lead sheath 4 and said socket connection and between said socketconnection and the lead sheaths 11 and 12 of the 30 insulated conductors7 may be made suitably by the application of thick layers of solder atthe places indicated by the numeral 8. To maintain the flow of oil fromone cable length to the next cable length contiguous thereto, the socketconnection 7 may be provided with a tubular extension 9 to which aflexible tube or pipe 10 may be connected with an oil-tight seal forforming an oil-conveying connection with the corresponding socketconnection on the cable length next contiguous thereto. By means of thisdevice, it is possible to maintain a flow of oil past the joint boxwithout it reaching the insulation of the cable. As shown in Figure 4, asubstantially similar result may be obtained by providing a connectionbranch 14 leading from the oil spaces within the common lead sheath andextending on the outside of the joint box to the corresponding commonlead sheath of the adjacent cable length. In the same manner, oil may beprevented from pene-'- trating into the potheads in which case the oilconveying tube leading from the socket connection or oil spaces-isplaced in communication with an oil equalizing tank provided, itnecessary, outside of the pothead.

I claim:-

1. The combination with joined sections of an oil-filled multi-conductorcable comprising insulated conductors respectively enclosed inindlvidual lead sheaths and having a lead sheath common to andsurrounding all of said sheathed insulated conductors, the spacesbetween saidlead sheaths and a lead sheath common to and surrounding allof said insulated conductors, the spaces between said individual leadsheaths and the common surrounding lead sheath being filled with oil, asocket connection for hermetically sealing said oil-filled spaces aroundthe end of said common surrounding lead sheath, said socketv connectionforming a permanent oil-tight seal with said common lead sheath andhaving tubular extensions respectively forming oil-tight seals with theindividual lead sheaths for said insulated conductors, and anoil-conveying tube for connecting the oil spaces of contiguous lengthsof the multi-conductor cable. i

' LUDWIG KUNST.

